1. Field of the Invention
This invention relates to movable closures, more specifically to a pivot mechanism mounted on a sliding window sash and located in the window jamb track for sliding one end of the sash along the track, and for preventing sliding, by pressing against the track when another end of the sash is rotated away from the track on the pivot mechanism.
2. Description of the Prior Art
Locking pivot shoes which lock in a window jamb track by bearing against some part of the track are disclosed in the prior art by many different designs.
In U.S. Pat. No. 2,778,068, patented Jan. 22, 1957 by A. Kaufman et al., an eccentric washer, located on a sash pivot shaft, protrudes through a slot in one side of the shoe bearing against a side wall of the track as the shaft is turned by the sash when the sash is rotated away from the track.
Elements which bite into the track are disclosed in Deal U.S. Pats. U.S.P.N. 4,452,012, June 5, 1984, and Marshik, U.S.P.N. 4,610,108, Sept. 9, 1986.
Deal discloses a cylinder concentrically mounted on the sash pivot shaft. The window jamb end of the cylinder which faces the bottom of the track is a cam which operates a bite spring mounted on the shoe. The bite spring is angled to resist the upward pull of the sash balance mechanism when the cam forces the end of the bite spring against the bottom of the track when the sash is rotated away from the track.
Marshik discloses a barrel cam concentrically mounted on the sash pivot shaft. A U shaped spring with outwardly directed serrated ends is fully seated around the cammed outer diameter of the barrel within the shoe. The serrated ends of the spring rest within slots in the sides of the shoe. When the sash is rotated, the cam surface of the barrel spreads the legs of the U spring, forcing the serrated ends outward by way of the slots, into the side walls of the track.
An assembly in which the top of the track is gripped by a shoe assembly is disclosed by D. M. Hettinger, Sept. 3, 1968 in U.S. Pat. No. 3,399,490. The track includes flanges which extend from the top edge of the side walls, over the channel so that a pair of longitudinal top walls are formed on each side of the track with slit opening access to the track.
A sash pivot shaft extends through the access slit and terminates in a first retainer disk. A plastic slider body is retained on the shaft between the retainer disk and the top walls, that is, the top inner faces of the track. A second cam disk on the pivot shaft is located above the top, with the cam surface engaging the outer faces of the top walls. The top walls roll inward toward the channel of the track, forming a longitudinal transition of the access slit for mating with the cam face. When the sash is rotated, the cam, riding out of the transition, pulls the shaft back, drawing the first disk up toward the top walls so that it forces the slider body against the inner faces of the top walls.
Assemblies which lock by bearing against side walls of the track for example, are disclosed in U.S. Pat. No. 3,055,062, Sept. 25, 1962, by L. E. Peters et al., and in U.S. Pat. No. 4,068,406, Jan. 17, 1978 by Wood.
Peters describes an assembly having a sash pivot shaft with a barrel cam portion. The slider body within the track is split into two legs at one end by a slot that is shaped to conform to the barrel cam when the sash is oriented with the track for sliding. When the sash is rotated away from the track, the cam spreads the legs so that they press into the inner faces of the side walls of the track.
Wood discloses a barrel cam within a slider body which is located in the track. The barrel cam includes a notch and snap-in retainer plug for receiving the sash pivot shaft. Apertures on each side of the slider body hold pistons which are forced outward by the barrel cam against the inner faces of the side walls of the track, when the cam is rotated by the sash as the sash is tilted away from the track.
In U.S. Pat. No. 4,718,194, patented Jan. 12, 1988, FitzGibbon et al. discloses a slider body diagonally split at one end. The split includes a portion shaped to conform to a sash pivot shaft actuated barrel cam when the sash is oriented with the track for sliding. One of the legs established by the split in the slider body includes a pin. The pin is forced against an inner face of a side wall of the track when the legs are spread by the cam as it rotates with the tilting window.
Assemblies which lock by bearing against the bottom of the track include those described by L. E. Peters, U.S. Pat. No. 3,184,784, May 25, 1965, D. M. Trout, U.S. Pat. No. 3,482,354, Dec. 9, 1969, and Anderson, U.S. Pat. No. 4,363,190, Dec. 14, 1982.
L. E. Peters discloses a sash pivot shaft entering the track through a longitudinal access slit formed by a pair of top walls of the track. A slider body, residing in the track includes a recess in the top facing surface, contoured for receiving a cam disk. A cam disk on the shaft is located below the inner faces of top walls, the bottom facing surface of the disk having the cam contour. The cam disk sits low in the recess when the sash is aligned with the track. When the sash is tilted from the track, the cam disk forces the slider body against the bottom of the track as the top facing surface of the disk is forced against the inner faces of the top walls.
In Trout, the center of the bottom wall of a track includes a longitudinal rib. The top of the track includes a pair of longitudinal top walls. A slider body located within the track includes a rotary spacer cam at the side facing the bottom wall, which is turned by the sash pivot shaft. The cam face of the spacer is grooved and mates with the ribbed wall. The cam is seated lowest when the sash is aligned with the track. When the sash is tilted, the cam is rotated out of alignment with the rib, and rises from the bottom wall to force the slider body against the inner faces of the top walls.
Anderson discloses a track with a pair of longitudinal top walls. A slider body located within the track includes a rotary spacer cam at the side facing the bottom wall, which is turned by the sash pivot. The cam is divided approximately into semicircles, with flats between them of lesser diameter. Resilient fingers mounted on the slider body parallel the flats on each side of the spacer cam when the sash is aligned with the track. When the sash is tilted, the cam is rotated so that portions of the cam are forced under two fingers, forcing them against the bottom wall as the slider body is held in the opposite direction by the inner faces of the top walls.